spacetoday.net: Many comets from other solar systems

Many comets from other solar systems

Posted: Fri, Jun 11, 2010, 7:14 AM ET (1114 GMT)
Comet McNaught (ESA)

The vast majority of comets in our solar system actually formed around other stars and were later captured by the Sun, scientists reported Thursday. Computer simulations show that more than 90 percent of the comets in the Oort Cloud, a spherical shell of icy bodies far from the Sun, likely originated from other stars, according to new computer simulations. The Sun formed in cluster of other stars also filled with icy objects; when the cluster dispersed the Sun captured many of these objects. The models explain why the Oort Cloud contains more objects than would be expected if all the objects formed around the Sun.